Better break out those shovels. A major snowstorm has arrived in Massachusetts tonight, the start of a storm system projected to leave Central and Western Massachusetts covered with a thick coating of snow that may be as deep as 18 inches in some areas.

The National Weather Service is reporting light snow falling n New Bedford, Worcester, Fitchburg, Orange, Springfield, Westfield, North Adams and Pittsfield while West Springfield had received about three inches by 10 p.m. tonight.

Speeds on the western end of the Massachusetts Turnpike have been lowered to 40 miles an hour due to snowy and slippery road conditions. Around 10 p.m., State Police reported that a tractor trailer unit had jackknifed near mile marker 85 near Charlton, forcing the closure of both westbound lanes.

But around Boston and the eastern part of the state, the storm is bringing rain and powerful winds that the NWS has warned could gust up to 50 miles an hour. There is also a coastal flood advisory out for Suffolk, Plymouth, Norfolk, Nantucket, Essex, and Barnstable from 8am to noon.

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The Cape and islands should also expect a large amount of rain and extremely high winds, bringing on possible power outages, rough seas, and wind damage, according to Barry Burbank, a meteorologist with boston.com weather partner WBZ-TV.

A weather service snowfall forecast map showed less than one inch accumulating within Route 128, in Southeastern Massachusetts, and on the Cape and islands. But the map predicted increasing snow amounts generally going west and north, with up to 18 inches expected in the northwest corner of the state.

The weather service warned of slippery driving conditions and reduced visibilities during heavy snow tonight through Thursday. The gradual change from snow to a wintry mix to rain will make for messy driving.

Friday will be sunny and dry with temperatures just below 40.

A second storm will move into New England Saturday night, but forecasting models indicate that it will remain further east, over the ocean, Simpson said.(Globe Correspondents Melissa Werthmann and Sarah Mattero contributed to this report.)